Anchor



May 4, 1954 H. P. SHIPLEY ANCHOR Original Filed Feb. 5, 1950 FIG. I. 22E i 4 Sheets-Sheet l INVENTOR HA RDWICK I? SH/PLEY ATTORNEY y 4, 1954 H.P. SHIPLEY 2,677,343

ANCHOR Original Filed Feb. 5, 1950 4 SheetsSheet 2 INVENT OR HA ROW/6K PSH/PLEY ATTORNEY May 4, 1954 H. P. SHIPLEY 2,677,343

ANCHOR Original Filed Feb. 3, 1950 4 Sheets-Sheet 5 INVENTOR nARowlax'F! SHIPLEY ATTORNEY y 4, 1954 H. P. SHIPLEY 2,677,343

ANCHOR Original Filed Feb. 5, 1950 4 Sheets-Sheet 4 n a o '0 u .0 9 E 58 AREA OF GROWN OPENING PROJECTED AREA OF PLATE ELEMENT (m THousANn Las)m -2 m: o

N w w g g, q t q INVENTOR i HARDWIOK P. SHIPLEY o m m 0 o qn N BYSClNVSflOl-U. m 3.LV'ld umouo vauv iuanow ATTORNEY WEIGHT OF ANOHORUNTHOUSAND LBS) Patented May 4, 1954 NlTED STATES TENT OFFICE Continuationof abandoned application Serial No. 142,243, February 3, 1950. Thisapplication June 17, 1953, Serial No. 362,429

(Granted under Title 35, U. S. Code (1952),

see. 266) 17 Claims.

This application is a continuation of application Serial No. 142,243,filed February 3, 1956, which has since become abandoned and, which inturn is a continuation-in-part of application Serial No. 531,239, filedApril 15, 1944, for an Anchor, now Patent No. 2,496,315.

lhe invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

The present invention relates to anchors and more specifically toanchors of a novel construction so as to be applicable to both large andsmall ships.

In prior known anchors, of the type which possess flukes rotatable alimited number of degrees with respect to the shank, the tendency hasbeen toward broad, fiat fiukes which, by presenting a wide surfacenormal to the direction of pull on the anchor, increase the holdingpower of the device. The use of such wide surfaces, however, has aserious disadvantage in the fact that many times the anchor has to bepulled a considerable distance before the fiukes take hold of theground. When the anchor is dropped, the wide fiukes often fall flat onthe surface of the ground so that when force is applied to the anchorthe flukes skid along the surface of the ground rather than burythemselves. The skidding will often continue until the flu-hes strikesome obstruction to rotate them into the ground. Also other types ofprior art anchors have employed a large mass of metal for the crown andutilized only relatively short, narrow flul-zes so that the holdingability of the device is supplied primarily through the sheer weight ofthe metal. However, this type is likewise unsatisfactory since it isburdensome to handle and store, it adds unnecessary weight to the vesselusing it, and it does not function eficiently.

The anchor relating to the present invention, on the other hand, offersmany improvements over prior anchors and thereby eliminates thedigging-in function prior to the gripping of the nukes, which makes itoperative immediately upon being dropped, and it exhibits a holdingpower which is greater than comparable anchors of the older types. Bymeans of the novel construction of the crown, and its associated diggingelement in the present invention, the flukes are assisted in quicklburying into the ground and are then maintained at their optimumoperating angle thereby providing desirable features which are not shownin prior anchors.

An object of the present invention is the provision of an anchor whichhas a positive diggingin function prior to the gripping of the fiukes.

Another object is to provide an anchor which has a digging element forrotating the fiukes to an initial gripping position.

Another object is to provide an anchor having a crown which will passsubstantially all of the earth dislodged and which will not clog up.

A further object is the provision of an anchor having a digging elementwhich assists the fiukes to assume the optimum position for holding.

Still another object is the provision of an anchor which exhibits a highholding power for its weight and size.

Yet another object is to provide an anchor having a scoop-shaped diggingelement and. a stool; on the crown end of the anchor to limit the depthto which the crown will be imbedded.

A further object is to provide an anchor of a type described, comprisingan elongated stock which not only acts as a stabilizer for preventingrotation or tumbling of the anchor, but also insures that the anchor,when dropped, will assume a digging-in position so that it willimmediately start to dig in when pulled upon.

A primary object of the invention is to provide an anchor of a typedescribed having a crown, dukes and rear stock which co-operate to causethe anchor substantially immediately upon reaching ground, hard or soft,to start to dig into the ground and before it is dragged a distanceapproximating its own length.

A final object is to provide an anchor having a digging element whichprevents the anchor 3 from inadvertently breaking free, and a stockwhich prevents the anchor from burying too deeply.

A further object of the invention is to provide an anchor which rapidlybegins its digging-in function once it is dropped, and which exhibits anoutstanding holding power for its weight when it is imbedded in theground but without any significant tendency to keep digging deeper intothe ground.

Other objects and features of the invention will become apparent tothose skilled in the art as the disclosure is made in the followingdetailed description of a preferred embodiment of the invention asillustrated in the accompanying sheet of drawings, on different scales,in which Fig. 1 is a plan view, partly in section, of the preferredanchor with its flukes closed.

Fig. 2 is a side view of the anchor with its flukes fully open andshowing the crown in cross-section.

Fig. 3 is an after end view of the crown showing the space for passageof earth dislodged by the digging element.

Fig. 4 is a perspective View of the anchor more clearly showing thecrown structure.

Fig. 5 is a view representing the digging or plate element as an areaprojected on a plane normal to the plane of the flukes; representativevalues of such areas for specific anchors being indicated in a table setforth in the specification.

Fig. 6 is a perspective view showing that the flukes will dig into theground even with the anchor on its side.

Fig. '7 is a graphical representation generally corresponding to certainvalues of typical anchors set forth in the aforesaid table, the curvethereof having as ordinates the ratio of areas of dirtdischarge openingsof crowns to the projected areas of digging or plate elements, andhaving as abscissae the weights of the associated anchors.

Fig. 8 is a graphical representation generally corresponding to certainvalues of typical anchors set forth in the aforesaid table, the curvethereof having as ordinates the moments area of digging or plateelements of the crown, and having as abscissae the weights of theassociate anchors.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views,there is shown in Fig. 1 a general view of the present inventioncomprising an anchor having a pair of flukes 2|, a shank 22, a stock 23,and a crown 24. At the extreme forward end of shank 22 there ispivotally mounted a shackle 25 for attachment to a cable, chain, or thelike, from a vessel, while the rear or after end of the shank extendsinto, and is completely surrounded by, crown 2 3. The after endextremity of the shank is provided with an aperture 21 whereby the shankis freely mounted upon the stock 23 so that it is able to oscillateabout the stock, independently of the crown. Hence, the center part ofthe stock 23 acts as a pivot shaft.

The stock 23 consists of an elongated member which is always positionednormal to the longitudinal axis of shank 22, and passes through theshank and crown 24. Associated with the stock 23, and forming anintegral portion thereof, is an abutment 28 which cooperates with awasher 2B and pin 3|) to hold crown 24 in position on the stock, but atthe same time permitting the crown to freely oscillate on the stock.

As is clearly apparent from the drawings, each of the flukes 2|comprises a comparatively extensive or fiat portion which is relativelywide at its after end and tapers to an edge in the form of a point ortip at its forward end so as to permit the fluke to freely enter and todig into the ground when force is applied to the anchor to pull itforward. In the embodiment described, the broad or fiat portions of theflukes 2| can be considered to lie in a single central plane that iscommon to and passes through both of them. The flukes may be providedwith reinforcing ridges such as better shown in Fig. 6, these ridgesextending along the shank-side edges of the flat portions of the flukes.

When the flukes are in the ground in an operating position such as shownin Fig. 2, their flat portions in the ground provide a drag that opposesthe pull on the anchor and in this manner produce the desired holdingpower. The flukes 2|, at their after ends, are attached to and form anintegral part of the crown 2 whereby they oscillate about the shaft 23along with the crown, there being one fluke positioned on each side ofthe shank 22.

The crown 24 comprises two side pieces, or webs 3i, positioned parallelwith shank 22 and located on either side thereof so as to form a supportfor flukes 2i. Connecting the two side pieces SI and extending normal totheir planes are digging members or plate elements or members 32 whichare positioned so as to be inclined with said central plane of theflukes 2!. Also connecting the side pieces, on the side opposite theflukes, is a cross-piece 33. The digging elements 32 consist of fiatplates positioned so as to define a dihedral angle of substantially 30to and preferably about 60, and since the plates are positionedequidistantly on either side of flukes 2|, then each plate makes anangle of from 15 to 40 and preferably about 30 relative to said flukes.It is evident that the plates slope outwardly and forwardly with respectto the flukes; that is, the plates are positioned at a slope making aforwardly flaring angle relative to the fiukes, as is apparent in Fig.2. These plates may be sharpened along their forward edges 34 tofacilitate digging in, while their interior surfaces 35, as limited bythe side pieces 3 l, form digging surfaces which function to enter theground prior to the flukes 2 l. The area of these digging surfaces maybe clearly seen in Figs. 4 and 5, and the manner in which they functionwill be described more fully hereinafter. It can be observed from Fig.2, that the digging surfaces are more extensive than the digging edges34.

As can be clearly seen in the views of Figs. 2 and 3, digging elements32 do not extend completely to close the crown 24, but when taken incooperation with the side pieces 3 i, define a specific passageway 36,through the crown, between the shank and the digging elements of an areato permit any ground dislodged by the digging elements to passtherethrough. The dimensions of passageway 36 relative to the otherelements of the anchor will be more fully described hereinafter.

Within the crown 24 and integral with shank 22 and extending on eitherside thereof, but spaced away from the side webs, are protuberances 38which function to contact the inner surface 35 of the digging elementsthereby to act as a limit-stop for the crown and flukes as they rotateabout stock 23. The height of the protuberances is such that, when oneof the digging elements seats thereagainst, that digging element isparallel to the longitudinal axis of the shank and the other element 32is at an angle in the range of about 30 to 80", but preferably about 60,with the shank, and the angle between the longitudinal axis of the shankand the fiukes is between 20 and 40 but preferably 30.

The operation of the present invention is typically as follows:

A sume that the anchor is deposited upon the ground or sea bed and thatat this stage rests upon the tips of the flukes 2| and the forward edge34 of the digging element, with the shank 22 extending at an anglesomewhat above the fiukes depending upon the amount of cable attached tothe anchor. The flukes are at a slight angle with the ground (about buthavent necessarily started to dig in. The stock serves generally toforce the anchor substantially to this position when the anchor is firstdropped and pulled.

As a forward force is imparted to the anchor, the digging element 32which is in contact with the ground immediately starts to dig in, evenbefore the flukes 2| take hold, inasmuch as the digging element is atquite a sharp angle with the ground. As penetration of the ground by thedigging element proceeds, the reaction of the ground on this elementcreates a torque on the crown and attached nukes tending to rotate theilulees, about the stock, acting as a pivot, downward into the ground.After this initial engagement of the flukes has been accomplished, thetorque developed by the action of the ground on element 32 combines withthe torque due to the downward component of the ground force on theflakes and assists in rotating the flukes into their final operativeangular position of approximately 39 with the center-line of the shank,such as seen in Fig. 2. As is apparent from Fig. 2, this angularposition of the flukes is obtained with the fiukes sloping outwardly andforwardly relative to the shank; that is, the flukes in this positionare at a slope making a forwardly flaring angle relative to the shank.One protuberance 38 abuts the digging element 32 which is not in theground, so that when the flukes are completely open they are at theoptimum angle for penetration and holding power.

Any forward motion of the anchor, which might result from theapplication of force thereto, will cause a strip of ground to bedislodged by the digging element, but the passageway 36, through thecrown, is so proportioned that the dislodged ground will freely andunobstructedly pass therethrough. By preventing the crown from cloggingup, the desired rotating torque imparted to the flukes is not destroyed.

In order that all of the earth dislodged may pass through passageway 36,this opening is designed to bear a definite relation to the size ofdigging elements 32 and the angle with which they are positionedrelative to flukes 2|. This relation varies with different sizedanchors, and is illustrated in Fig. 2 wherein is shown the foremosu andrearmost edges of the digging element 32 projected onto a planeperpendicular to the plane of the flukes. For the anchor of Fig. 2, itwill be found that the distance measured along the perpendicular plane,between the projections of these edges, is less than the narrowest partof the passageway through the crown. In other words the projecteddistance 81, for the anchors as shown in Figs. 2 and 5, is less than thedistance from the rearmost edge of element 32 to the nearest portion ofthe shank. This last distance is indicated as the dimension 36' in Fig.2. The relationship of this distance 36' to the projection distance 31for anchors of various weights constructed in accordance with theprinciples of this invention is shown in a table subsequently set forthin columns 1 and 4.

It is obvious that the amount of earth dislodged by the digging elementis directly proportional to the projected area of the digging surface(Fig. 5). As the anchor is varied in weight for application to ships ofdifferent sizes, then this projected area should also vary in size; andin order to insure free movement of the dislodged earth through thecrown, it is necessary that the area of the opening 36 varyproportionately. Experience has shown, however, that as the weight ofthe anchor increases, the accompanying increase in area of the openingmay be somewhat lessened relatively and the graph of Fig. 7 shows thetrend of this relationship. In the graph the ratio of the area of theopening to the projected area of the plate element is plotted againstweight of the anchor and it can be seen that the curve falls off atfirst and then from about 10,000 lbs. up it practically levels off to astraight line. The equation for the curve of Fig. '7 may be stated as Inan anchor of the type described, the torque which the digging elementsexert to rotate the fiukes downward into the ground may be expressed infamiliar engineering language as the moment of the digging element aboutthe crown pivot point, or in other words the projected area of thedigging element times the moment arm. The graph of Fig. 3, which is aplot of the mo ment of digging element (crown plate) against weight ofthe anchor, shows that this relationship goes up in a straight line asthe size of the anchor increases, and the curve may be expressed asy:0.3386w+27.5005.

The following table has been compiled to better illustrate therelationship between the various elements which make up the presentinvention, and the manner in which these elements vary as the size ofthe anchor varies. The headings of the various columns may be more fullydescribed as follows:

0. Weight of the anchor in pounds.

1. Height of the opening (36) in inches.

2. Width of the opening (35) in inches.

3. Area of the opening (35) in square inches (columns 1x2).

4. Projected height of digging plate (see 3?, Figs. 2 and 5).

5. Width of plate (same as column 2).

6. Projected area of digging plate (Fig. 5) (columns 4x5).

7. Ratio of area of opening to projected area of the plate (column 3/6).

8. Lever arm of plate element (from plane of flukes).

9. Moment area of plate element (columns 6X8) 10. Ratio of the area ofopening to the moment area of the plate element (column 3/9).

11. Ratio of the moment area of the plate element to the area of theopening (column 9/3).

12. Ratio of height of opening to the projected height of the plateelement (column l/ l).

13. Logm of weight in pounds.

Ht. Width Area Proj Moment Anchor Open- Open- Open- Proj. g Area B31110{if Area Rfltlo B3110 B8410 E"? Wt. ing ing ing Ht. P1 P1 P1. 2 in Lbs.at at at P]. as 2 Element 6 Elem'ent Element 9 3 4 Lb Rem Rear Rear 4X56X8 It is obvious that curves may be plotted from the data given in theforegoing table and a comparison of the features of the presentinvention made thereby. The plot of Fig. 7 was made from the data ofcolumn '7, while Fig. 8 is from column 9, both curves, however, beingextended out beyond the limits shown in the table.

In addition to assisting the flukes to rotate into the ground, thedigging elements 32 serve several added purposes. It will be noted inFig. 2 that the element which is not engaging the ground abuts theprotuberance 33 when the flukes are fully open and also thatprotuberance 38 is constructed of such a length that the element 32maintains a position substantially parallel with shank 22. In thismanner there is effectively produced a safety feature to prevent theanchor from freeing itself, should it bury itself below the level of thestock. If, by some circumstance the anchor should penetrate the grounduntil the upper digging element also engages the ground, then any grounddisturbed by this upper element will pass directly through the crownwithout irn-- parting any rotation to the flukes, since the plane of thedigging element is parallel with the motion of the anchor. It can beclearly seen that if the upper digging element did not come to restsubstantially parallel to the shank and the direction of applied force,that any rotation which it would apply to the flukes would be eithercounter to the ground engaging rotation of the opposite digging element,thereby tending to break the flukes out of the ground, or else therotation would be so as to make the flukes dig even deeper, both ofwhich are undesirable. It will be noted that the upper digging elementwill not roll up the dislodged earth, nor clog up, to impart a counterrotation to the flukes, even through the protuberance 38 is in contactwith the upper digging element, because there is still sufficientclearance on either side of the protuberance to pass the earth.

The stock 23, of the present invention, is made comparatively long,relative to the width of the flakes, and thereby serves several distinctpurposes. First, that the anchor will always ultimately position itselfwith its flukes parallel with the ground, even though it shouldprimarily hit the ground in a position such as shown in Fig. 6. It canbe seen in that view that the three points of contact are so spaced, andthe center of gravity of the anchor is so off balance, that the anchorcannot remain in this position, and so will fall over and dig in.Another purpose served by the relatively long stock is that it functionsto prevent the anchor from burying itself too deeply into the ground.Once the flukes have started to engage the ground, they will continue topenetrate until a point is reached where the stock is flush with thelevel of the ground. The comparatively long stock will not readily sinkinto the ground, and by distributing over a wide area the force tendingto bury the anchor, the continued penetration is effectively halted. Ifan anchor be permitted to continue penetration until some hardobstruction is hit below the ground, it would be so firmly imbedded thatits removal would be impossible without damage to the flukes or shank.The present anchor is designed to offer maximum holding power when itsflukes are fully open and it is buried to the center line of the shank.

A common failing of prior art anchors which have no crown stock, is thatshould one fluke strike an obstruction in the ground, the anchor becomesunbalanced and thereafter will tumble, or rotate, and ultimately willpull out of the ground. The long stock on the present anchor in additionto its other advantages will obviate this difiioulty and maintain thedevice balanced at all times.

Fig. 6 clearly illustrates another advantage of the preesnt invention inrespect to the shape of the forward portion of the flukes, and it can beseen that the tapering, pointed flukes always present a point,positioned for penetration into the ground, even though the anchorshould fall, as shown.

From the foregoing description, the advantages of the present anchorover those of the prior art may be summarized as follows. Where theanchor crown is provided with a stock but has no positive diggingelements as in certain wellknown anchors, the flukes are not forciblyengaged by the ground during setting of the anchor and such anchors havebeen known to skid on hard ground for a considerable period beforeengaging their flukes. Furthermore, once the flukes engage, the crowncontinues to move along the surface of the ground thereby permitting theangle of attack of the flukes to increase whereby the anchor continuesto bore into the ground to great depths and forcing the relatively thin,sharp shank,- to plow into the ground. This has the overwhelmingdisadvantage of making it impossible to withdraw the anchor withoutbending or damaging, or even destroying, the flukes and the shank. Suchanchors, even when provided with a crown stock, have been known to enterinto hard ground a distance of twenty-five feet and to have beenrendered completely useless by the forces applied thereto during theirsubsequent removal.

Where an anchor is provided with digging elements but no stock on itscrown, the digging elements will cause the flukes to forcibly engage theground during setting of the anchor to provide rapid imbedding of theflukes but because the digging elements must always be designed to havea greater angle of attack than the flukes to be effective, the diggingelements will burrow into the ground more rapidly and deeply than theflukes to cause the flukes eventually to assume an angle which willbring them up out of the ground thereby rendering the anchorinoperative.

It is apparent, then, that by providing both digging elements and astock on the crown of the anchor as in the present invention, thesedisadvantages of the prior art are obviated. The present anchor causesrapid setting of the flukes and prevents the shank from plowing into theground and eliminates the tendency of the digging elements to bore toodeeply once the stock engages the surface of the ground, the diggingelements having too small an area to drag the stock down below thesurface of the ground. As the angle of attack of the flukes on theground is not permitted to increase on full digging in of the crown,there is no tendency of the anchor to bore rapidly downward toundesirable depths even though the anchor may drag due to excessivewinds blowing on the anchored vessel. This allows the anchor to beretrieved with ease and without damage.

Because the plate of the upper digging element assumes a positionparallel to the longitudinal of the shank during setting of the anchor,there is no tendency, when the anchor is being set in mud, for the upperdigging element to exert a counter-torque acting to force the flukes outof contact with the ground, and the fact that the protuberance on theshank is spaced from the webs of the digging elements, prevents mud fromballing up in the upper digging element to produce such acounter-torque.

It should be understood, of course, that the foregoing disclosurerelates to only a preferred embodiment of the invention and thatnumerous modifications or alterations may be made therein withoutdeparting from the spirit and the scope of the invention as set forth inthe appended claims.

What is claimed is:

1. An anchor comprising a shank and a crown, said crown having a air offlukes pivotally mounted on the shank for rotation, said. crownincluding webs, and a substantially rectangular plate element supportedby said webs, said plate element having substantially parallel interiorand exterior flat surfaces, said plate element having a forward endadapted to dig into the ground and rock the crown relative to the shankso as to rotate the flukes downward into the ground, said plate elementbeing positioned at a slope making a forwardly flaring angle relative tosaid flukes, said plate element having its rearward end spaced away fromthe nearest portion of the shank by a distance greater than thedifference in distance between the projections of the said forward andrearward ends on a plane perpendicu- 10 lar to the plane of the flukes,and a protuberance on said shank to contact the interior flat surface ofsaid plate element and thereby limit move-- ment of the crown relativeto the shank.

2. An anchor comprising a shank and a crown, Said crown having a pair offlukes pivotally mounted on the shank for rotation, said crown includingwebs, a substantially rectangular plate element supported by said webs,said plate element having substantially parallel interior and exteriorflat surfaces, said plate element adapted to dig into the ground at itsforward end and rock the crown relative to the shank so as to 1'0 tatethe flukes downward into the ground, said plate element being positionedat a forwardly flaring angle relative to said flukes, said plate elementhaving its rearward end spaced away from the nearest portion of theshank by a distance greater than the difference in distance between theprojections of the said forward and rearward ends on a planeperpendicular to the plane of the flukes, and a protuberance on saidshank extending at right angles thereto, said protuberance arranged tocontact the interior flat surface of said plate element and therebylimit movement of the crown relative to the shank.

3. An anchor of a type described comprising, in combination, a shank anda crown enveloping one end of said shank, a pivotal connection joiningsaid shank and said crown, said crown having a pair of substantiallyfiat flukes extending forwardly thereof each having a side edge that iswide rearwardly and tapers inwardly forwardly substantially to a tip,said crown comprising a pair of spaced webs, said webs being on oppositesides of said shank, said crown comprising a plate element between saidwebs, said plate element having a forwardly facing interior diggingsurface inclined to the central plane of the flukes, said diggingsurface being substantially fiat and having a sharp forward edgeextending forwardly of said webs, said plate element having a rearwardedge spaced from the shank but closer the central plane of the flukesthan its forward edge, and said plate element being adapted to dig intothe ground and rock the crown relative to the shank so as to rotate theflukes downward into the ground, said plate element having its rearwardend spaced away from the nearest portion of the shank by a distancegreater than the difference in distance between the projections of saidforward and rearward edges on a plane perpendicular to the plane of theflukes, and an elongated stock extending outwardly from both sides ofsaid crown so that said anchor when cle posited on the ground can restupon the tips of said flukes and on said forward edge of said plateelement.

4. An anchor of a type described comprising, in combination, a shank anda crown enveloping one end of said shank, a pivotal connection joiningsaid shank and said crown, said crown having a pair of substantiallyflat flukes extending forwardly thereof each having a side edge that iswide rearwardly and tapers inwardly forwardly substantially to a tip,said crown comprising a pair of spaced webs, said webs being on oppositesides of said shank, said crown comprising plate elements between saidwebs, each of said plate elements having a forwardly facing interior digging surface inclined to the central plane of the flukes, said diggingsurface being substantially flat and having a sharp forward edgeextending forwardly of said webs, each of said plate elements having arearward edge spaced from the shank but closer the central plane of theflukes than its forward edge, each of said plate elements being adaptedto dig into the ground and rock the crown relative to the shank so as torotate the flukes downward into the ground, each of said plate elementshaving its rearward end spaced away from the nearest portion of theshank by a distance greater than the difference in distance between theprojections of said forward and rearward edges on a plane perpendicularto the plane of the flukes, a projecting element on said shank adjacentsaid crown for engaging said crown and thereby constituting stop means,and stock means extending outwardly beyond said flukes.

5. An anchor as defined in claim 4 but further characterized by saidplate element comprising an exterior flat surface substantially parallelto said interior surface, and forming an angle of about 15 to 40 withsaid flukes.

6. An anchor of a type described comprising, in combination: a shank inthe form of a straight bar, said bar having a shackle means at itsforward end and an after end, a unitary open-ended crown comprising aweb on each side of said after end of said shank, said crown alsocomprising digging members joining said webs and lying on opposite sidesof said shank, said crown further comprising flukes extending from saidwebs, said flukes having broad flat portions, said digging memberscomprising flat elements at a slope making a forwardly flaring angleabout 15 to 40 with respect to the axis of said shank when said flukesextend parallel to said axis of said shank, a pivot connection betweensaid shank and crown, whereby said shank and crown are separatelyoscillatable on said connection, said flukes having side edges withportions that taper inwardly forwardly substantially to a tip, and arelatively elongated stock means extending from both sides of said crownbeyond said flukes.

'7. An anchor as defined in claim 6 but further characterized by aprojecting element on each of a pair of sides of said shank adjacentsaid pivot connection generally intermediate said flat elements, eachprojecting element having a face for bearing against an adjacent flatelement.

8. An anchor of a type described comprising, in combination: a shank inthe form of a straight bar, said bar having a shackle means at itsforward end and a single aperture in its after end, a unitary open-endedcrown comprising a web on each side of said after end of said shank,each web having an aperture, said crown also comprising digging membersjoining said webs and lying on opposite sides of said shank, saiddigging members'having sharp forward edges, said crown furthercomprising flukes extending from said webs, said flukes having broadflat portions, said digging members comprising flat elements at a slopemaking a forwardly flaring angle about 15 to 40 to the axis of saidshank when said flukes extend parallel to said axis of said shank, therear size of the opening of said crown being on account of said slopingelements less than but over one-half that of the forward opening of saidcrown, and a relatively elongated stock journalled in said aperture andsaid apertures in said webs, whereby said shank and crown are separatelyoscillatable on said stock, each of said flukes having a tapered forwardedge portion coming substantially to a tip.

9. An anchor as defined in claim 8 but further characterized by a narrowcross piece joining the rear edges of said webs, paralleling said stock,

10. An anchor as defined in claim 8 but further characterized by saidforward edges of said digging elements extending forwardly of said webs.

11. An anchor of a type described comprising, in combination: a shank inthe form of a straight bar, said bar having a shackle means at itsforward end and a single aperture in its after end, a unitary open-endedcrown comprising a web on each side of said after end of said shank,each web having an aperture, said crown also comprising digging membersjoining said webs and lying on opposite sides of said shank, saiddigging members having sharp forward edges, said crown furthercomprising flukes extending from said webs, said flukes having broadflat portions, said digging members comprising flat elements at a slopemaking a forwardly flaring angle about 15 to 40 with respect to the axisof said shank when said flukes extend parallel to said axis of saidshank, the area of the rear opening of said crown being on account ofsaid sloping elements less than but over one-half that of the forwardopening of said crown, and stop means on said shank adjacent the crownadapted to engage said crown for limiting tilting of said crown beyond aposition where one of said digging members is substantially parallel tosaid shank.

12. An anchor as defined in claim 11 but further characterized by saidstop means being protuberances on said shank in line with said openingsin said crown but narrower than said openings so as not to bar themovement of ground through said openings.

13. An anchor comprising a shank, an open crown at one end of saidshank, a pivotal connection joining said shank and said crown, a pair offlukes secured to and extending forwardly of said crown, said flukeshaving a forward digging end, said crown comprising web means and a pairof digging elements supported by said web means so that each elementgenerally makes a forwardly flaring acute angle relative to said flukes,each digging element having an interior surface facing toward said shankand a sharp forward end adapted to dig into the ground and rock thecrown and flukes relative to the shank so as to rotate said flukesdownward into the ground whereby they can dig into the ground, eachdigging element having its rearward end closer to said shank than itssaid forward end but spaced from said shank so that dirt dug up by saiddigging elements can pass through the space therebetween, an elongatedstock means extending outwardly from both sides of said crown beyondsaid flukes, a pair of protuberances extending from a pair of sides ofsaid shank adjacent said crown for engaging the interior surfaces ofsaid digging elements, said protuberances being of lengths to engage afirst of said digging elements to restrain the other of said diggingelements at a slope making a forwardly flaring acute angle with respectto said shank, the sum of said acute angles being less than ninetydegrees.

14. An anchor of a type described comprising in combination a shankhaving a forward end provided with a shackle means and having an afterend, a unitary open-ended crown pivoted to said shank at said after end,said crown comprising a pair of similar digging members spaced from saidshank on opposite sides thereof whereby dirt is adapted to pass betweensaid members, said web means extending to and between said diggingmembers, said digging members having substantially parallel forwarddigging edges and rearward surface portions that are more extensive thansaid digging edges and extend from said edges to the rear of said crown,a pair of flukes secured to and extending forwardly of said crown, saidfiukes having broad portions lying substantially in a plane making aforwardly flaring acute angle with respect to said surface portions ofsaid digging members, each of said fiukes having a side edge with aforward portion that tapers substantially to a tip, and a relativelyelongated stock means extending from both sides of said crown and beyondsaid fiukes.

15. An anchor of a type described comprising in combination a shankhaving a forward end provided with a shackle means and having an afterend, a unitary open-ended crown pivoted to said shank at said after end,said crown comprising a pair of similar digging members spaced from saidshank on opposite sides thereof whereby dirt is adapted to pass betweensaid members, and web means extending to and between said diggingmembers, said digging members having substantially parallel forwarddigging edges and rearward surface portions that are more extensive thansaid digging edges and extend from said edges to the rear of said crown,a pair of fiukes secured to and extending forwardly of said crown, saidfiukes having broad portions lying substantially in a plane making aforwardly flaring acute angle with respect to said surface portions ofsaid digging members, each of said fiukes having a side edge with aforward portion that tapers substantially to a tip, a relativelyelongated stock means extending from both sides of said crown and beyondsaid iiukes, and stop means comprising a portion on each side of saidshank, each of said stop portions having a face for bearing against aco-operative portion on said crown for limiting pivoting movement ofsaid crown to a position wherein the maximum movement of said surfaceportions is to positions substantially parallel to said shank.

16. An anchor comprising a shank, an open crown at one end of saidshank, a pivotal connection joining said shank and said crown, a pair offlukes secured to and extending forwardly of said crown, said flukeshaving a forward digging end, said crown comprising web means and a pairof diggin elements supported by said web means so that each elementgenerally makes a forwardly fiaring acute angle relative to said fiukes,each digging element having a sharp forward end adapted to dig into theground and rock the crown and fiukes relative to the shank so as torotate said flukes downward into the ground whereby they can dig intothe ground, each digging element having its rearward end closer to saidshank than its said forward end but spaced from said shank so that dirtdug up by said digging elements can pass through the space therebetween,an elongated stock means extending outwardly from both sides of saidcrown beyond said flukes, and stop means at said crown for engaging afirst of said digging elements to restrain the other of said diggingelements at a forwardly flaring acute angle with respect to said shank,the sum of said acute angles being less than ninety degrees.

17. An anchor of a type described comprising, in combination, a shankhaving a forward end provided with a shackle means and having an afterend, said shank having an open crown and a pair of fiukes pivotedthereto at said after end, said crown comprisin a pair of diggingelements spaced from said shank on opposite sides thereof and providingopen passage means in the space between said digging elements for thepassage of dirt therethrough, said pair of flukes having broad portionslying substantially in a plane making a forwardly flaring acute anglewith respect to each of said digging elements, stock means extendinglaterally outwardly of said crown on both sides thereof and beyond saidbroad portions of said fiukes, said stock means being substantiallyparallel to said plane, and stop means for limiting pivoting movement ofsaid crown and flukes to a position wherein said plane makes a forwardlyflaring acute angle with respect to said shank, the sum of the last saidacute angle and each one of the first said acute angles being less thandegrees.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 308,646 Williams Dec. 2, 1884 314,149 Pettes Mar. 17, 1885439,921 Williams Nov. 4, 1890 532,606 Sproat Jan. 15, 1895 913,367Downie Feb. 23, 1909 1,497,693 Myers June 17, 1924 2,249,546 DanforthJuly 15, 1941 FOREIGN PATENTS Number Country Date 261,980 Great BritainDec. 2, 1926 610,779 Germany Mar. 22, 1935

